1. Field of the Invention
The present invention relates to a cuff for a blood pressure monitor, and more particularly to a cuff for a blood pressure monitor provided with an elastic member for securing a fluid bag to a living body.
2. Description of the Background Art
To measure a blood pressure value, generally, a cuff provided with a fluid bag for pressing an artery located within a living body is wound around the body surface, and arterial pressure pulse waves caused in the artery by inflation/deflation of the fluid bag are detected to measure the blood pressure value. Here, the cuff refers to a band-shaped structure having a bladder, which can be wound around a part of a living body, for use in measurement of arterial pressure of an upper limb, a lower limb or the like by introducing fluid such as gas or liquid into the bladder. Thus, the cuff represents the concept including the fluid bag as well as members for winding the fluid bag around the living body. Particularly, the cuff wound around and fitted on an arm is also called an arm band or a manchette.
When mounting the cuff for a blood pressure monitor, it is necessary to unfailingly wind the cuff main unit around the living body in order for the fluid bag to be reliably secured to the measurement site of the living body. In the case of a conventional cuff for a blood pressure monitor, however, the infallible winding is not always guaranteed because a subject of the measurement is entrusted with the winding operation. Variation in winding operation leads to variation in measurement value, making it difficult to realize accurate and stable measurement of the blood pressure values.
To realize the reliable winding of the cuff main unit, a cuff for a blood pressure monitor that has an elastic member called a curled elastic member contained in the cuff main unit in addition to a fluid bag is known (see, e.g., Japanese Patent Laying-Open Nos. 2003-210423, 61-238229, 2002-209858). The curled elastic member serves to retain the annular shape of the cuff main unit, and is wound annularly on the outside of the fluid bag inside the cuff main unit, so as to make the cuff main unit radially changeable in size. When the cuff for a blood pressure monitor having such a curled elastic member is fitted to the living body, the curled elastic body presses the fluid body against the living body at an appropriate pressing force to secure the same on the measurement site, so that reliable winding of the fluid body around the living body can be realized repeatedly.
A specific configuration of the cuff for a blood pressure monitor provided with the curled elastic member as described above and a way of winding the same are disclosed, e.g., in Japanese Patent laying-Open Nos. 10-033490, 07-136132, 10-033489, and 07-124127. Hereinafter, the configurations and winding manners of the cuffs for a blood pressure monitor disclosed in these publications will be described.
Firstly, in the cuff for a blood pressure monitor of a conventional example 1 disclosed in Japanese Patent Laying-Open No. 10-033490, the cuff main unit containing an air bag and a curled elastic member therein is inserted through a ring member to fold it back at a prescribed position. A sheet-shaped joining member such as a velcro fastener is provided on the outer surface of the cuff main unit. With the cuff for a blood pressure monitor having such a configuration, after the cuff main unit is wound around a measurement site, it is folded back outward at the position defined by the ring member, and the folded part of the cuff main unit is secured to the outer surface of the unfolded part thereof by means of the sheet-shaped joining member.
In the cuff for a blood pressure monitor of a conventional example 2 disclosed in Japanese Patent Laying-Open No. 07-136132, the cuff main unit containing an air bag and a curled elastic member therein has a pivotable operation plate on one end, and has a ring on the other end, which can be engaged with a hook provide on the inner surface of the operation plate. With the cuff for a blood pressure monitor having such a configuration, after the cuff main unit is wound around a measurement site, the ring is engaged with the hook provided on the inner surface of the operation plate, and while the engagement is being maintained, the operation plate is pivoted to secure the cuff main unit to the living body.
In the cuff for a blood pressure monitor of a conventional example 3 disclosed in Japanese Patent Laying-Open No. 10-033489, the cuff main unit is formed of an inner binding belt and an outer binding belt. The inner binding belt contains an air bag and a curled elastic member therein, and is in a cylindrical form and expandable as is elastically wound around a measurement site. The outer binding belt is less elastic and wound over the inner binding belt. With the cuff for a blood pressure monitor having such a configuration, the measurement site of the living body is inserted through the inner binding belt of the cylindrical form, with the outer binding belt yet to be wound. After the inner binding belt is brought into close contact with the living body, the outer binding belt is fastened from above the inner binding belt to secure the cuff main unit to the living body.
In the cuff for a blood pressure monitor of a conventional example 4 disclosed in Japanese Patent Laying-Open No. 07-124127, a cover unit halved in a circumferential direction is provided on the outside of a curled elastic member. The halves of the cover unit are provided with tab members at the connecting portion thereof, to protrude outward from the respective halves. The curled elastic member is fixed to the inner peripheral surfaces of the halves of the cover unit. With the cuff for a blood pressure monitor having such a configuration, the tab members are pinched with fingers to narrow the distance therebetween so as to increase the diameter of the curled elastic member in opposition to the elastic force thereof, and while maintaining the diameter-increased state, the cuff main unit is applied to a measurement site. Thereafter, the fingers having pinched the tab members are released so as to secure the cuff main unit to the living body.
However, with any of the cuffs for a blood pressure monitor of the above-described conventional examples 1 through 4, the cuff-winding operation is considerably troublesome, since the curled elastic member needs to be configured to maintain a diameter smaller than that of a measurement site of the living body in the non-fitted state, such that the curled elastic member when fitted can reliably press the air bag against the measurement site of the living body. More specifically, upon fitting of the cuff main unit, the curled elastic member in the diameter-decreased state needs to be increased in diameter so as to be fitted to the measurement site of the living body. It is this diameter-increasing operation of the curled elastic member that makes the cuff fitting operation troublesome. Particularly, in the case of a cuff for a blood pressure monitor for household use, the subject himself/herself needs to wind the cuff main unit around one arm using the other hand, which is accompanied by very troublesome operations of spreading the cuff main unit in the diameter-decreased state and mounting the same on the arm that should be done with a single hand. The operation of dismounting the cuff main unit after measurement is also burdensome.
To alleviate such troublesomeness, the cuff for a blood pressure monitor of the above-described conventional example 4 is provided with the tap members on the outer peripheral surface of the cuff main unit to facilitate the operation of spreading the curled elastic member. With this configuration, however, it is necessary to put certain power to the fingertips for sufficiently increasing the diameter of the curled elastic member. Thus, the mounting/dismounting operations of the cuff main unit are still troublesome for elderly people and women relatively weak in physical strength.